Copyright Goodheart-Willcox Co., Inc. Section 13-3 Nutrition Across the Lifespan 347 may increase or decrease. Ninety percent of food allergies are caused by eight food allergens: milk, eggs, tree nuts, peanuts, wheat, soybean, fi sh, and crustacean shellfi sh. People with food allergies must modify their diets to avoid foods that contain allergens. Food Intolerances Food intolerance is an adverse reaction to the consumption of certain foods. Usually symptoms appear more slowly than in the case of food allergies and are milder. Symptoms include upset stomach, minor headaches, and loss of sleep. Food intolerance is caused by defi ciencies or reactions in the digestive tract. Lactose intolerance is a form of food intolerance in which the body is unable to digest dairy products that contain lactose. Lactose is a sugar that is broken down into glucose by the enzyme lactase. Some people’s bodies produce insuffi cient amounts of lactase. Instead of being broken down, lactose ferments in the intestines. This causes symptoms ranging from bloating and nausea to diarrhea. Lactose intolerance is controlled by limiting lactose intake or omitting dairy products from the diet. High Blood Pressure Blood pressure is the force of blood pushing against the walls of the arteries. High blood pressure usually has no symptoms until it leads to problems with the heart, brain, or kidneys. High blood pressure can cause arteries to harden, leading to a heart attack or stroke. Once high blood pressure develops, it usually lasts a lifetime. However, it can often be controlled. Many times, the cause of high blood pressure is not known. Weight loss, physical activity, and a healthful diet are usually recommended to help prevent and control high blood pressure. A healthful diet includes foods low in sodium, fat, and cholesterol, and rich in potassium. Diabetes In a healthy body, the hormone insulin helps move the glucose used for energy throughout the body. In the body of a person with diabetes, the production of insulin is limited, or the body cells do not respond properly to insulin. Glucose stays in the blood where it can cause serious damage to body organs. Complications include the destruction of small blood vessels in the eyes, the slow deterioration of the kidneys, cardiovascular complications, and nerve damage. Some of the symptoms of diabetes include increased thirst and urination, unusual weight loss, frequent infections, and slow-healing wounds. People with diabetes must monitor their blood glucose level. They must learn to carefully control their sugar intakes while still eating a diet high in complex carbohydrates. Weight control and regular exercise are also important. Some people with diabetes must receive insulin to replace the natural supply. Ask your school nurse to demonstrate how to measure a person’s blood pressure with a sphygmomanometer. This instrument includes an inflatable cuff that is wrapped around the upper arm and tightened, while a read out displays the person’s blood pressure in the arteries. Wellness Awareness